Imagemagick closing SSH connection?

this is really weird.
when i run imagemagick’s identify -verbose command from the command line on certain images, my SSH (putty) connection closes !

the command is this:
/usr/bin/identify -verbose ./IMG_0173.jpg > /tmp/wtf

the image can be downloaded here:

it hasn’t happened without verbose,
and it doesn’t always happen.
the command also runs startlingly slow.

i’m concerned about putting this command in a php script,
what will happen to the script ?